After yanking more than $150 billion out of U.S. stocks last year, individual investors have been on a buying spree in 2013, with $17 billion flowing back in, according to the latest data from the Investment Company Institute.

With the Dow flirting with 14,000 and just 200 odd points away from a new all-time high, have individual investors missed out on the rally?

Maybe.

"In the past, this level of insider selling has been indicative of a coming downturn or at least a plateau in the market," said David Coleman, insider trading analyst at Argus Research.

The last time the Vickers index hit a level above nine was mid-March of last year. That was just before stocks closed out their best first quarter in more than a decade.

Shortly thereafter, the Dow, which had just topped 13,000, slipped below that mark and largely stayed there until late July, when stocks rallied back with a vengeance on hope for more stimulus from central bankers in Europe and the United States.

In 2011, insiders also rapidly sold out of stocks just a few weeks before S&P downgraded the credit rating of the United States.

Last week's CFTC Commitment of Traders report showed a big swing from bearish (or neutral) to bullish and that's typically an indicator of a coming plateau, or drop in the market, said Ari Wald, a technical strategist at PrinceRidge.

In the span of two months, the percentage of bullish traders jumped to 55% from 37%.

"It usually means that a lot of bullish bets have already been in place," said Wald. "It doesn't mean the market will fall apart but it looks like time to take a more neutral approach."

CNNMoney's Fear & Greed Index has also seen a big swing. The index has been in extreme greed over the past week, hitting a record high of 94 (the index only goes to 100). It has since backed off a little, but is still in extreme greed. Just a couple of months ago, it was deep into fear, hovering around 27 in mid November.

If Wald's predictions are true, that big swing may be yet another sign that a change is coming.